Truncus arteriosus (TRUNG-kus ahr-teer-e-O-sus), or persistent truncus arteriosus, is a rare heart defect that's present at birth (congenital). If your baby has truncus arteriosus, one large vessel, instead of two separate vessels, leads out of the heart. Also, the two lower chambers of the heart are missing a portion of the wall dividing them. As a result of truncus arteriosus, oxygen-poor blood that should go to the lungs and oxygen-rich blood that should go to the rest of the body are mixed together. This creates severe circulatory problems.
If left untreated, truncus arteriosus is usually fatal during the first year of life. Surgery to repair the heart and blood vessels is generally successful, especially if the repair occurs before your baby is 2 months old.
Signs and symptoms of truncus arteriosus often develop in the first few weeks of life. They include:
When to see a doctor
Some signs of truncus arteriosus may indicate a problem that needs urgent care. If your baby experiences any of the following signs and symptoms and you can't see your baby's doctor immediately, seek emergency medical care:
Truncus arteriosus occurs during fetal growth when your baby's heart is developing and is, therefore, present at birth (congenital). In most cases the cause is unknown. An overview of typical heart structure and function is helpful in understanding the defects of truncus arteriosus.
The heart's four chambers are:
Normal heart development
Also during this process, the ventricles develop into two chambers separated by a wall (septum).
Truncus arteriosus in newborns
Truncus arteriosus in a newborn is also called persistent truncus arteriosus, because an early stage of heart development persisted until birth.
In addition to the primary defects of truncus arteriosus, the valve controlling blood flow from the ventricles to the singe large vessel (truncal valve) is often defective, allowing blood to flow backward into the heart.
If your baby has truncus arteriosus, one very large vessel leads out of the heart, instead of two separate vessels, and there's a hole in the wall between the ventricles (ventricle septal defect). ...
While the exact cause of congenital heart defects, such as truncus arteriosus, is unknown, several factors may increase the risk of a baby being born with a heart condition. These include:
The abnormal heart structures of truncus arteriosus result in severe problems with blood circulation. Because the ventricles aren't separated and all blood exits from a single vessel, the oxygen-rich blood and the oxygen-poor blood mix together — resulting in blood that doesn't carry enough oxygen. The mixed blood flows from the single large vessel to the lungs, the arteries of the heart and the rest of the body.
If your baby has truncus arteriosus, the abnormal circulation of blood usually results in:
Complications later in life
Common signs and symptoms of these complications include shortness of breath, dizziness, fatigue and a sensation of rapid, fluttering heartbeats (palpitations).
Truncus arteriosus in adults
Preparing for your appointment
When you contact your baby's doctor about your concerns, he or she may ask you to schedule an appointment or immediately refer you to a heart specialist for children (pediatric cardiologist). This will depend on the severity of the signs and symptoms you have described over the phone.
Because there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready for your appointment and what you can expect from your doctor.
What you can do
It's also helpful to prepare a list of questions ahead of time so you can make the most of your time together with your baby's doctor. Here's a sampling of questions you might want to ask:
In addition to the questions that you've prepared to ask your baby's doctor, don't hesitate to ask questions that may come up during your appointment.
What to expect from your doctor
When your baby was born, your baby's height, weight and head circumference were recorded, and these measurements are taken at all regularly scheduled appointments with your child's doctor. He or she will repeat these measurements during a special appointment and determine if there has been any delay in growth.
Your baby's doctor will also listen to your baby's lungs to assess his or her breathing and the possibility of fluid in the lungs. The doctor will listen to your baby's heart to determine if there are irregular heartbeats (arrhythmia) or an abnormal whooshing sound caused by turbulent blood flow (heart murmur).
For babies with truncus arteriosus, much of their medical care is provided by a pediatric cardiologist along with a pediatric cardiac surgeon and often a whole team of specialized staff.
Tests and diagnosis
In order for the pediatric cardiologist to check the condition of your baby's heart and make a diagnosis, he or she will order one or more tests:
In a baby with truncus arteriosus, the echocardiogram reveals the single large vessel leading from the heart, a hole in the wall between the left and right ventricles, and sometimes an abnormality in the valve between the large vessel and the ventricles.
Because an echocardiogram shows the flow of blood, it may also reveal blood moving back and forth between the two ventricles and the amount of blood flowing to your baby's lungs. The amount of blood can indicate the risk of high blood pressure in the lungs.
Treatments and drugs
Surgery can often repair the heart of an infant with truncus arteriosus. Sometimes multiple procedures or surgeries will be necessary. Before your baby undergoes surgery, he or she may receive more frequent feedings to ensure proper nutrition and medications to improve heart and lung function.
After corrective surgery, your child will need lifelong follow-up care with a cardiologist to monitor his or her heart health. The cardiologist may recommend that your child limit physical activity, particularly intense competitive sports. Your child will need to take antibiotics before dental procedures and other surgical procedures to prevent infections.
Because the conduit does not grow with your child, one or more follow-up surgeries to replace the conduit are usually necessary as he or she gets older. Newer surgical procedures that use a cardiac catheter inserted into a blood vessel in the leg that are then threaded slowly up to the heart are being developed to replace the conduit without the need for traditional heart surgery. In addition, cardiac catheterization with an inflatable balloon tip can be used to open up an obstructed or narrowed artery, which may delay the need for follow-up surgery.
Coping and support
Caring for a baby with a serious heart problem, such as truncus arteriosus, can be challenging. Here are some strategies that may help make it easier:
In most cases, congenital heart defects, such as truncus arteriosus, can't be prevented. If you have a family history of heart defects or if you already have a child with a congenital heart defect, you and your partner may consider talking with a genetic counselor and a cardiologist experienced in congenital heart defects before you make a decision about becoming pregnant.
If you're thinking about becoming pregnant, there are several steps you can take to help ensure a healthy baby, including:
Last Updated: 2010-07-13
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